dt-bindings: irqchip: ti, sci-inta: Update for unmapped event handling

The new DMA architecture introduced with AM64 introduced new event types:
unampped events.

These events are mapped within INTA in contrast to other K3 devices where
the events with similar function was originating from the UDMAP or ringacc.

The ti,unmapped-event-sources should contain phandle array to the devices
in the system (typically DMA controllers) from where the unmapped events
originate.
Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Reviewed-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20201020073243.19255-2-peter.ujfalusi@ti.com

Documentation/devicetree/bindings/interrupt-controller/ti,sci-inta.yaml

@@ -32,6 +32,11 @@ description: |
                        | | vint  | bit  |  | 0 |.....|63| vintx  |
                        | +--------------+  +------------+        |
                        |                                         |
+                       |      Unmap                              |
+                       | +--------------+                        |
+ Unmapped events ----->| |   umapidx    |-------------------------> Globalevents
+                       | +--------------+                        |
+                       |                                         |
                        +-----------------------------------------+
 
   Configuration of these Intmap registers that maps global events to vint is
@@ -70,6 +75,11 @@ properties:
         - description: |
             "limit" specifies the limit for translation
 
+  ti,unmapped-event-sources:
+    $ref: /schemas/types.yaml#definitions/phandle-array
+    description:
+      Array of phandles to DMA controllers where the unmapped events originate.
+
 required:
   - compatible
   - reg